In the early ‘90s, the British fishing town of Portishead produced a namesake band that made beautifully disturbing music: anguished vocals over chilled hip-hop break beats, accented by Spaghetti Western guitars and eerie atmospherics.

Singles “Sour Times” and “Glory Box” trickled onto the charts, and made the self-effacing trio unlikely stars as well as huge sampling favorites by hip-hop artists.

After two well-received albums, the group’s core of Beth Gibbons, Geoff Barrow and Adrian Utley took a decade-plus hiatus. In 2008, they reconvened around a more volatile sound and a new studio album, "Third." And on Wednesday, the prodigal trio – augmented by three musicians – returned triumphantly to a sold-out Aragon. Expectations hung in the air like one of Utley’s sustained guitar notes, and the band in many ways shattered them for the better.

This was a heavier, more dynamic Portishead. Barrow often grumbled in interviews about the group being miscast as a between-the-headphones uneasy listening experience in the ‘90s (special spite would be reserved for those who dubbed the trio’s sound “trip-hop”). But there was always turmoil and toughness in this music, and Wednesday’s concert was all about magnifying it: The wide-angle sound was matched by an equally prodigious background video screen, which turned Utley’s foot peddles and Barrow’s drum sticks into larger-then-life weapons in stark black and white.

Some things hadn’t changed since Portishead last played Chicago in the late ‘90s. Gibbons’ voice still pierced through veils of hair, and she shyly turned her back to the audience during instrumental interludes. Once she gripped the microphone stand as if it were the only object between her and a nervous breakdown, her stance reflecting lyrics racked with doubt and despair. But on this night, she was in a fighting mood, her voice rising as it powered through a matrix of drums and feedback in “Threads” and “We Carry On.”

Her voice now has an even more supple quality – perhaps because she’s no longer chain-smoking her way through the set. Her tone is full and rounded in the lower register, with a slight quiver when she pushes it higher. She was perfectly matched with a band that emphasizes extremes, from near-silence to crashing bedlam.

Barrow orchestrated everything from a position behind Gibbons, presiding over a nest of turntables, mixers, guitar and percussion. He brought a level of violence to his scratch breaks on “Over” and especially “Cowboys” that would’ve fit just fine on a Slayer album. When pounding beats on snares, timbales and drum pads, he rarely doubled the drummer’s rhythms; rather the two often played contrasting patterns that gave the music a metallic edge (the industrial war zone of “Machine Gun”) or a racing pulse (the frantic futurism of “Chase the Tear”).

As Barrow played the song’s insistent bass pattern in a chair a few feet from a hunched-over Gibbons, Utley extracted shivering notes from his guitar with a slide. The fans stood silently rapt through the entire performance, the intimacy shattered only when Gibbons let loose a wordless vocal melody that wrapped itself like a ghost around the tail end of the song. It was great theater as much as it was a demand to hear Portishead in a new way.